This combustion device for a melting furnace is used in melting furnaces for melting glass, metal, or another object to be melted, and cross fired types and end-port types are well known as melting furnaces provided with a combustion device for a melting furnace.
A cross fired furnace has a structure in which a combustion device N for a melting furnace is lined up on a lateral section of a melting zone, along the direction in which an charging port 4i for inputting raw material into the melting zone 2 and an extraction port 4e for extracting a melted object are lined up (see FIG. 2). An end-port melting furnace has the charging port 4i for inputting raw material provided to a lateral location on the upstream side of the melting zone 2, and the extraction port 4e for extracting the melted object provided below the front surface on the downstream side of the melting zone. The combustion device N is provided in the vicinity of the charging port 4i (see FIG. 22).
The present inventors have proposed a configuration for such a combustion device for a melting furnace, comprising a center ejection path for ejecting gas fuel and an annular peripheral ejection path positioned about the periphery thereof, wherein the distal end side of the peripheral ejection path is made to project from the center ejection path and is formed in a tapered shape in which diameter is reduced in progress toward the distal end side, and gas fuel is ejected so as to converge at the distal end side.
Using this configuration makes it possible to form a strong firm flame (a strong, rectilinearly long flame) and to suppress the generation of NOx while dispensing with the need for a dedicated cooling fluid for cooling the fuel ejector (e.g., see Patent Document 1).